Glucosyltransferase and phosphate (Pi) translocator are key enzymes in glucan biosynthesis. The reprogramming of the mRNAs encoding glucosyltransferase and Pi translocator by environment-wide factors that induce the isomerization of Glutamate Dehydrogenase (GDH) was studied by northern analysis. Equal concentrations of total RNA from environment-wide treated peanuts were probed with those GDH-synthesized RNAs that were homologous to the mRNAs encoding glucosyltransferase and Pi translocator. Those environment-wide factors (CTP, 4NTPs) up-regulated the mRNA encoding Pi translocator by about eight-fold and down-regulated the mRNA encoding glucosyltransferase by at least five-fold. Conversely, those factors (3NTPs, GTP) up-regulated the mRNA encoding glucosyltransferase by about seven-fold and down-regulated the mRNA encoding Pi translocator by at least five-fold. The level of the mRNA encoding glucosyltransferase was directly related to the accumulated cellulosic biomass. But a threshold level of the mRNA encoding the Pi translocator was necessary in order for cellulosic biomass to begin to accumulate. The reciprocal relationships between the mRNAs encoding Pi translocator and glucosyltransferase, in the light of the isomeric sequence similarities among the GDH-synthesized RNAs, suggested that the mRNAs were reprogrammed by the GDH-synthesized RNAs. These results could be useful in the environmental manipulation of the structure and yield of cellulose.

Phosphate translocators and glycosyltransferases are important enzymes in glucan biosynthesis (Karnezis et al., 2000). Phosphate translocator regulates the counter exchange of Pi and triose phosphates between the chloroplast and cytoplasm, thereby controlling starch synthesis in the chloroplast (Portis, 1982). Starch synthesized in the chloroplast is converted to maltose (Schleucher et al., 1998) and then transported into the cytoplasm (Niityla et al., 2004), where glucose is released from maltose (Chia et al., 2004). Glucose is converted to hexose phosphates for metabolism, and uridine 5'-diphosphate-glucose destined for cellulose biosynthesis (Swissa et al., 1980). It has been suggested that cellulose biosynthesis involves chain initiation, elongation and termination (Peng et al., 2002), with the participation of glucosyltransferase in the chain initiation reaction (Saxena and Brown, 1997). Whereas the molecular biology of Pi translocator (Mitsukawa et al., 1997; Smith, 1999; and Muller et al., 2007) and the regulation of sucrose and starch accumulation by phosphate have been studied (Heldt et al., 1977), the environment-wide regulation of cellulosic biomass accumulation by Pi translocator and glucosyltransferase has not been studied. Cellulose, a fibrous molecule, is the primary component of economically important products such as wood, cotton, paper and animal feed. Because cellulose can also be hydrolyzed to glucose and then to ethanol and other biofuels, there is a lot of interest in understanding the environmental regulation of its biosynthesis and accumulation in plants. Such an understanding might permit the manipulation of environmental factors so that plants produce modified cellulose with improved properties. Although cellulose is the most abundant macromolecule on earth, its biosynthesis remains an unresolved topic (Varner, 1995). This has made it difficult to research the environmental factors that limit its accumulation in plants. Peanut is ideal for this research because it is superior to other crops in possessing the ability to absorb phosphate from low phosphate availability soils (Ae and Otani, 1997).